1. Field of the Invention
The invention relates to a material for substantively preparing yarns or plied yarns, especially sewing threads and preferably those of polyester, in the form of an oil/water dispersion and process for the preparation of such materials.
2. Description of the Prior Art
German Offenlegungsschrift No. 21 61 813 discloses the use of mixtures of diorganopolysiloxanes as lubricants for organic fibers. The organic radicals, linked to the silicon have 1 to 5 carbon atoms. Mixtures of diorganopolysiloxanes of different viscosities are used. Even though these mixtures are preferably employed without using purely organic oils and/or waxes or wax-like materials, the simultaneous use of such materials, such as, natural or synthetic oils, paraffin and beeswax may be possible.
German Offenlegungsschrift No. 25 35 768 discloses diorganopolysiloxane lubricants for organic fibers prepared by emulsion polymerization. These are characterized by the fact that they have an average viscosity of 22,000 cSt (=mm.sup.2 /sec) at 25.degree. C. and are present in admixture with at least one paraffin wax and/or at least one polymer consisting of fluorine atoms and carbon atoms, and, optionally, chlorine atom. Fibers treated with such a preparation should have an improved lubricity and sewability. A typical example of such a preparation consists of a mixture of diorganopolysiloxanes, paraffin wax and polytetrafluoroethylene.
The treatment of sewing thread on bobbins with aqueous baths, which contain 6 to 20 weight percent of organosilicon polymers, is described in German Offenlegungsschrift No. 27 53 200. Pure silicone oils, as well as polysiloxane-polyoxyalkylene block copolymers can be used for this purpose.
German Offenlegungsschrift No. 28 16 196 discloses staple fiber yarns having a uniformly low friction in conjunction with a satisfactory softness. This is achieved by using a wet-paraffinizing material which consists of (in weight percent):
(a) 18 to 40% paraffin, having a melting range of 45.degree. to 60.degree. C.;
(b) 2 to 8% of one or more alkylimidazolines having the formula (I) ##STR1## in which R represents C.sub.12 -C.sub.22 alkyl, alkenyl or hydroxyalkyl,
R.sub.1 represents H, C.sub.1 -C.sub.22 aliphatic or aromatic acyl, PA1 R.sub.2 represents H, C.sub.1 -C.sub.4 alkyl or hydroxyalkyl, PA1 n represents numbers from 2 to 6, and PA1 X represents a halogen, C.sub.1 -C.sub.4 alkyl sulfate, C.sub.1 -C.sub.4 dialkyl phosphate or C.sub.1 -C.sub.4 alkyl carboxylate anion; PA1 R.sub.1 represents C.sub.1 -C.sub.4 alkyl, PA1 R.sub.2 represents H or C.sub.1 -C.sub.4 alkyl, and PA1 n represents numbers from 0 to 6; PA1 x represents numbers from 20 to 40, and PA1 y numbers from 25 to 1000; PA1 R represents C.sub.8 -C.sub.18 alkyl or alkenyl, and PA1 n represents numbers from 3 to 12; as well as PA1 (a) about 5 to 80 weight percent of a silicone oil having a viscosity of from about 500 to 50,000 mm.sup.2 /sec at 25.degree. C.; PA1 (b) about 10 to 80 weight percent of a wax with a melting point of not less than about 40.degree. C.; PA1 (c) about 1 to 10 weight percent of fatty acids with from 6 to 22 carbon atoms; PA1 (d) about 0.4 to 12 weight percent of cationic imidazolinium salts; and PA1 (e) from about 0 to 10 weight percent of ethoxylated fatty amines,
(c) 1 to 7% of one or more amine oxides having the general formula (II) ##STR2## in which R represents C.sub.8 -C.sub.12 alkyl or alkenyl,
(d) 2 to 9% of an ethylene oxide/propylene oxide block copolymer having the formula (III) EQU H--(C.sub.2 H.sub.4 O).sub.y --(C.sub.3 H.sub.6 O).sub.x --(C.sub.2 H.sub.4 O).sub.y --H (III)
in which
(e) 0 to 5% of a polyglycol ether having the formula (IV) EQU R--O(C.sub.2 H.sub.4 O).sub.n --H (IV)
in which
(f) 0 to 2% of a copolymer of vinylpyrrolidone and vinyl acetate, in which the weight ratio of VP/VAC can vary from 3:7 to 8:2,
with the remainder adding up to 100 weight percent consisting of water.
Practical trials, however, have shown that such known preparations still have various disadvantages. For example, one disadvantage is that uniform preparation of the yarn is not always achieved. As a consequence, the so-called seam length turns out differently. The seam length is understood to be that length of seam, which can be obtained under specified, reproducible conditions before the sewing thread breaks. If the yarns or plied yarns are prepared on bobbins, the inner layers of the bobbins frequently have a different amount of finish from the outer layers of the bobbins.
In other cases, in spite of a sufficiently high and uniform coating, friction values are obtained which are too high and too irregular, causing uneven running during sewing or knitting which leads to frequent machine stoppages. In addition, irregular seam or stitch patterns result. The friction also varies at various speed ranges, which occur, for example, during sewing.
Also, sewing threads of polyester, which are preferred, in the form of single-ply yarns or weakly twisted multi-ply yarns, always exhibit a clear decrease in breaking strength of about 20% after the use of such known substantive paraffin pareparations.